Stanford alum Jonathan Martin took in a Cardinal-USC game in L.A. last month. / Kirby Lee, USA TODAY Sports

by Tom Pelissero, USA TODAY Sports

by Tom Pelissero, USA TODAY Sports

Attorney Ted Wells was interviewing estranged Miami Dolphins tackle Jonathan Martin for a second time Thursday as Wells' NFL-backed investigation into issues of workplace conduct continues, a person with knowledge of the meeting told USA TODAY Sports.

The person spoke on condition of anonymity because they weren't authorized to speak on the investigation, which is now entering its fifth week.

Martin, who left the Dolphins and sought treatment for undisclosed mental health issues after a cafeteria prank Oct. 28, first met with Wells for more than seven hours Nov. 15.

Wells' investigation continued at the Dolphins' facility the following week and figures to return there before he files his report, which the NFL has said will be made public.

The league named Wells special counsel to lead the investigation Nov. 6, three days after Martin's representatives turned over evidence of alleged abuse at the hands of teammate Richie Incognito and other Dolphins.

Incognito, 30, also has met with Wells. He cut a deal last month that delayed his expedited grievance hearing and allowed the Dolphins to suspend him for an additional two games in exchange for reducing his maximum financial loss to two game checks.

Barring another negotiated extension, the Dolphins must reinstate or waive Incognito by Dec. 16.